Former French president Nicolas Sarkozy has been released from jail, three weeks into a five-year prison term for taking part in a criminal conspiracy.

He will be subject to strict judicial supervision and barred from leaving France ahead of an appeal trial due to be held next year.

On 21 October, the former centre-right president, 70, was sentenced to five years for conspiring to fund his 2007 election campaign with money from late Libyan dictator Muammar Gaddafi.

During his incarceration, he was visited by Justice Minister Gérald Darmanin. The visit prompted 30 French lawyers to file a complaint against Darmanin, highlighting what they said was a conflict of interest as Darmanin was a former colleague and friend of Sarkozy's.

Speaking to a court in Paris via video link on Monday morning, Sarkozy described his time in solitary confinement as "gruelling" and "a nightmare".

Since entering prison, Sarkozy has been held in a cell in the isolation wing.

He had a toilet, a shower, a desk, a small electric hob and a small TV – for which he paid a monthly €14 (£12) fee – and the right to a small fridge.

He also had the right to receive information from the outside world and family visits, as well as written and phone contact – but was in effect in solitary confinement. He was allowed just one hour a day for exercise, which he did by himself in the wing's segregated courtyard.

Two bodyguards were stationed in nearby cells, which the interior minister Laurent Nuñez said was due to Sarkozy's status. There was "obviously a threat against him", Nuñez said.

Sarkozy was president from 2007 to 2012. Ever since he left office, he has been dogged by criminal inquiries and for months had to wear an electronic tag around his ankle after a conviction last December for trying to bribe a magistrate for confidential information about a separate case.